Free-radically cured compositions are becoming more popular in many industries. The fast cure associated with these materials makes them attractive. There is a need in many industries to have materials that are very soft when cured (low modulus), have rubber-like properties (e.g. high elongation, are hydrophobic and are tough. Specifically, the properties are important to applications such as conformal coatings in the electronics industry, where encapsulation of sensitive electronic circuitry and protection from moisture and shock are crucial to the operation of electronic equipment. Optical fibers are very fragile and they need to be coated with very soft, rubbery materials to protect them from damage. It is usually desirable that seals and gaskets be made from materials that are to some degree yielding such that they are able to deform and tightly fill the space they are designed for, which may include slight irregularities. Golf ball covers are often radiation-cured, and today most of the materials being used in the manufacture of golf ball covers are very soft in order for the player to get more “feel” when striking the ball. Plastics are inherently very difficult to adhere other materials to and there are very few ways to adhere to plastics without some sort of pretreatment of the surface of the substrate. It has been found that low modulus materials often adhere better to plastics than harder, more rigid materials.
Silicones have fond a niche for many of the applications listed above, however, there is broad resistance to the continuing and/or expanded use of silicones in an industrial manufacturing environment due to environmental contamination associated with their manufacture and use. Furthermore, although silicones do posses very rubbery characteristics when cured, they often lack sufficient toughness for many applications. For at least these reasons there is a continuing need to find viable and less expensive replacement for silicones.